Moments of nucleon generalized parton distributions from lattice QCD

Abstract

We present results on the lower moments of the nucleon generalized parton distributions within lattice QCD using two dynamical flavors of degenerate twisted mass fermions. Our simulations are performed on lattices with three different values of the lattice spacings, namely, a=0.089fm, a=0.070fm, and a=0.056fm, allowing the investigation of cutoff effects. The volume dependence is examined using simulations on two lattices of spatial length L=2.1fm and L=2.8fm. The simulations span pion masses in the range of 260 to 470MeV. Our results are renormalized nonperturbatively, and the values are given in the MS̄ scheme at a scale μ=2GeV. They are chirally extrapolated to the physical point in order to compare with the experiment. The consequences of these results on the spin carried by the quarks in the nucleon are investigated. © 2011 American Physical Society.